Description

In the Linux kernel, the following vulnerability has been resolved:

net: enetc: Do not configure preemptible TCs if SIs do not support

Both ENETC PF and VF drivers share enetc_setup_tc_mqprio() to configure
MQPRIO. And enetc_setup_tc_mqprio() calls enetc_change_preemptible_tcs()
to configure preemptible TCs. However, only PF is able to configure
preemptible TCs. Because only PF has related registers, while VF does not
have these registers. So for VF, its hw->port pointer is NULL. Therefore,
VF will access an invalid pointer when accessing a non-existent register,
which will cause a crash issue. The simplified log is as follows.

root@ls1028ardb:~# tc qdisc add dev eno0vf0 parent root handle 100: \
mqprio num_tc 4 map 0 0 1 1 2 2 3 3 queues 1@0 1@1 1@2 1@3 hw 1
[ 187.290775] Unable to handle kernel paging request at virtual address 0000000000001f00
[ 187.424831] pc : enetc_mm_commit_preemptible_tcs+0x1c4/0x400
[ 187.430518] lr : enetc_mm_commit_preemptible_tcs+0x30c/0x400
[ 187.511140] Call trace:
[ 187.513588] enetc_mm_commit_preemptible_tcs+0x1c4/0x400
[ 187.518918] enetc_setup_tc_mqprio+0x180/0x214
[ 187.523374] enetc_vf_setup_tc+0x1c/0x30
[ 187.527306] mqprio_enable_offload+0x144/0x178
[ 187.531766] mqprio_init+0x3ec/0x668
[ 187.535351] qdisc_create+0x15c/0x488
[ 187.539023] tc_modify_qdisc+0x398/0x73c
[ 187.542958] rtnetlink_rcv_msg+0x128/0x378
[ 187.547064] netlink_rcv_skb+0x60/0x130
[ 187.550910] rtnetlink_rcv+0x18/0x24
[ 187.554492] netli...

Classification

CVE ID: CVE-2024-56649

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.08% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/66127f0d1ecf00604aeab71132bde398fd9ec7c9
https://git.kernel.org/stable/c/b718b68a9964181e24d15138a09ce95785a19002
https://git.kernel.org/stable/c/b2420b8c81ec674552d00c55d46245e5c184b260

Timeline